If you are looking for the WMS to pull through your stomach quickly and carry other things such as creatine, bcaa, etc. You should drink the WMS with those mixed in then wait about 15-20 minutes and drink your protein. When more than 30% of the drink is items other than WMS the osmosolity (spelled that wrong) gets to thick and use lose the value of it being digested and entering your system uber quick. If you are just looking for a complex carb to meet a requirement in your caloric intake, than there is no problem in mixing whey and WMS.